Chemical embossing techniques have been used widely in industry in the manufacture of floor, ceiling, and wall coverings; desk, table and counter tops; coated and impregnated fabrics; and like articles, as more particularly described in U.S. Pat. Nos. 3,293,094, 3,293,108 and 3,458,337, the disclosures of which are incorporated herein by reference.
Such chemical embossing techniques have normally involved coating a base material, such as an asbestos sheet, with a substantially uniform layer of a resinous material such as polyvinyl chloride. A foaming or blowing agent, such as azodicarbonamide, is normally uniformly dispersed in the resinous material and is adapted, upon subsequent heating to a sufficiently elevated temperature, to decompose and to liberate gaseous decomposition products to expand and create the foamed, blown resinous product.
One aspect of such chemical embossing techniques has comprised the printing of selected, predetermined areas of the surface of heat-foamable resinous material, prior to the heating, with a foam-growth-controlling printing ink composition which is capable of affecting and changing the foam-growth of those selected, predetermined areas, when the heat-foamable resinous materials are subsequently heated to the required elevated temperature.
Such foam-growth-controlling printing ink compositions have contained either: (1) agents for inhibiting or suppressing the decomposition of the foaming or blowing agents to thus decrease the resulting expanding gaseous action on the foamable resinous materials and to correspondingly decrease the foam-growth in the selected, predetermined areas to which they are applied; or (2) agents for catalyzing or accelerating the decomposition of the foaming or blowing agents to thus increase the resulting gaseous action on the foamable resinous materials and to correspondingly increase the foam-growth in the selected, predetermined areas in which they are applied.
As a consequence, the surface of the resulting, foamed or blown resinous materials have been given an embossed or relief pattern effect containing relatively higher areas or lands and relatively lower areas or valleys, thus providing excellent surface texture.
The foam-growth-controlling printing ink compositions have thus contained both: (1) the foam-growth-controlling agents; and (2) the pigments, ink, dyes or other coloring materials, whereby the resulting embossed or relief pattern effects have been made to coincide very accurately and very precisely with the ink-printing pattern, thus creating excellent visual and tactile effects which are in substantially perfect alignment and registry at all times.
More specific details and particulars of such chemical embossing techniques may be found in the United States patents previously referred to herein and such details and particulars are incorporated herein by reference thereto.
Although a number of organic, solvent-based foam-growth-controlling printing ink compositions have been used previously in such chemical embossing manufacturing techniques, and have proved to be relatively successful therein, it is always desired to improve upon existing commercial and industrial techniques. Organic solvent-based printing inks are relatively expensive, are usually very difficult to remove or clean from printing equipment, are occasionally not adaptable for use with conventional commercial printing equipment, are often flammable or have relatively low flash points which are unfortunately conducive to dangerous or hazardous conditions, frequently cause significant waste, ecological, or pollution problems, and sometimes required costly and time-consuming solvent-recovery programs.
U.S. Pat. Nos. 4,083,907 and 4,191,581 describe a water-based ink composition for use in chemical embossing using triazole foam-growth-controlling agents such as benzotriazole. Other, more acidic foam-growth-controlling agents such as trimellitic acid anhydride have been used in solvent-based ink compositions but have not been thought suitable for water-based ink compositions because of their high degree of acidity.